Highly Efficient Gas-Diesel Hybrid Engine Developed at ETHZ

Researchers at ETH Zurich have developed an internal combustion engine that emits less than half the CO2 compared to a regular engine, without compromising its performance. The researchers at Lino Guzzella’s laboratory redesigned a conventional diesel engine to run on 90% natural gas. Instead of a spark plug, as is standardly used in natural gas engines, this engine is ignited with a small amount of diesel injected directly into the cylinder. Thus, the engine achieves a highly efficient combustion with a maximum efficiency of 39.6%.

As a key element, the researchers have developed an electronic combustion control. A sensor measures pressure in the cylinders to adapt the amount and timing of diesel continually, allowing an engine system with highest efficiency. The researchers also linked the natural gas-diesel engine to a small electric motor to further reduce consumption. “At the moment, we are concentrating particularly on the temperature in the catalytic converter,” says Tobias Ott, a doctoral student working on the project. For the converter to get up and running, it has to reach at least 300°C. The researchers want to solve the problem by modified control of the engine during the warm-up.

The researchers believe that the success of their engine depends critically on its production costs. Even though this solution may not be very cheap, it is comparatively cost-effective. Since their concept is based on technology that already exists, it can be implemented quickly.

The project was supported by the Competence Center Energy and Mobility (CCEM) and by the Swiss Federal Office of Energy. The reference article was published in the journal Energies.